This is a note to let you know that I've just added the patch titled spi: Fix erroneous sgs value with min_t() to the 5.16-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: spi-fix-erroneous-sgs-value-with-min_t.patch and it can be found in the queue-5.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ab97f2e6a340df4aa2f64d5c8586cf84490c886b Author: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> Date: Wed Mar 16 17:53:17 2022 +0000 spi: Fix erroneous sgs value with min_t() [ Upstream commit ebc4cb43ea5ada3db46c80156fca58a54b9bbca8 ] While computing sgs in spi_map_buf(), the data type used in min_t() for max_seg_size is 'unsigned int' where as that of ctlr->max_dma_len is 'size_t'. min_t(unsigned int,x,y) gives wrong results if one of x/y is 'size_t' Consider the below examples on a 64-bit machine (ie size_t is 64-bits, and unsigned int is 32-bit). case 1) min_t(unsigned int, 5, 0x100000001); case 2) min_t(size_t, 5, 0x100000001); Case 1 returns '1', where as case 2 returns '5'. As you can see the result from case 1 is wrong. This patch fixes the above issue by using the data type of the parameters that are used in min_t with maximum data length. Fixes: commit 1a4e53d2fc4f68aa ("spi: Fix invalid sgs value") Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Suggested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220316175317.465-1-biju.das.jz@xxxxxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index ed4e6983eda0..4e459516b74c 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1021,10 +1021,10 @@ int spi_map_buf(struct spi_controller *ctlr, struct device *dev, int i, ret; if (vmalloced_buf || kmap_buf) { - desc_len = min_t(unsigned int, max_seg_size, PAGE_SIZE); + desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE); sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len); } else if (virt_addr_valid(buf)) { - desc_len = min_t(unsigned int, max_seg_size, ctlr->max_dma_len); + desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len); sgs = DIV_ROUND_UP(len, desc_len); } else { return -EINVAL;